The 41-year-old apologised as he was being led away to prison saying he did not set out to do it.

The former heroin addict convicted of murdering his friend turned to the bereaved family at his sentencing hearing on Monday and said: 'I'm sorry, I didn't set out to do this.'

Jackson was given the mandatory life sentence by Justice Isobel Kennedy at the Central Criminal Court this morning. During the hearing Mr Hamilton's uncle Robert Denby read a victim impact statement that described the family's suffering since David's death.

He said the 'world came crashing down' and that when they rushed to his bedside after hearing he had been stabbed, 'it never entered our heads that someone so big and strong and full of life could die. No words can express how broken-hearted we are.'

Mr Hamilton was described as a talented drummer who developed a love of music when he learned to play the flute as a boy. He had played with bands in Ireland and abroad, most notably with international touring outfit Extreme Rhythm.

His younger brother Peter, who attended each day of the trial with parents Victor and Margie, looked up to Dave who, in turn 'constantly looked out for him and advised him'.

Mr Denby said the 'terror and sadness' of what had happened to David would live with the family forever and that every family get-together was marred by his absence.

Detective Garda Michael Dolan of Gurranabraher Garda Station also spoke at the hearing.

Speaking with counsel for the Prosecution Tom O'Connell, he said Jackson has 73 previous convictions dated from February 17 1998 to February 2015. He said most were for road traffic and public order offences while he had 17 convictions for theft and burglary.

His most serious conviction was for sale or supply of heroin for which he was given a three-year sentence in 2008.

Det Gda Dolan agreed that he had no previous convictions for violence.

Speaking to defence counsel Dominic McGinn, Detective Garda Dolan also agreed that Mr Jackson had shown remorse and had co-operated with the garda investigation.

Mr McGinn also pointed out that Jackson had pleaded guilty to manslaughter but not guilty to murder. This plea was not accepted by the prosecution.

Justice Isobel Kennedy told Jackson that he had been convicted of murder and that she was giving him the mandatory sentence of life. She backdated the sentence to May 4, 2012 when he first entered into custody.

During the trial, the court heard that Jackson and Mr Hamilton were heroin users who went to a house on Kerryhall Road on May 4, 2012 to inject heroin.

Ms Pamela McHale, from Cork, who was a friend of Jackson's, told the court that they had bought two bags of heroin earlier that day worth €50 each.

An argument started after Jackson had cooked up the first bag of heroin and injected himself and Ms McHale but had difficulty finding a vein to inject Mr Hamilton.

Ms McHale said: 'Dave was giving out and Peter was like "calm down" but Dave wanted to go to another fella's house who he said could inject proper.'

They began smoking the second bag on a piece of tinfoil but Ms McHale said Mr Hamilton became increasingly agitated and wanted to take the heroin to the other house so that he could inject.

'Peter and Dave got in a fight,' she said. 'He was trying to pull the foil off Peter and Peter gave him a dig and Dave gave Peter a dig. Peter picked something up from the table and he swung.'

At the time she did not see what Mr Jackson had picked up and she said Mr Hamilton left the room and became hysterical.

It was some minutes before she noticed that there was 'blood everywhere' and that his shirt was soaked with blood. It was around this time that she became aware of the knife that had been used to stab Mr Hamilton.